Faulting and Folding

1. Faulting and Folding By Maria, Chris, Kayla, and Taylor

2. Fault -Faults are fractures in the crust along which movement has taken place. -They can be recognized in road cuts where sedimentary beds have been offset a few meters. Large faults have displacements of hundreds of kilometers and consists of many interconnecting fault surfaces. These fault zones can be many kilometers wide and are often easier to identify from high-altitude photographs than at ground level.

3. Parts Of Fault The major types of faults are normal faults, reverse faults, thrust faults, and strike-slip faults. A normal fault occurs when the hanging wall block moves down relative to the footwall block. Reverse faults are faults in which the hanging wall block moves up relative to the footwall block. Thrust faults are faults with dips of less than 45 percent . Strike-Slip faults are faults in which the movement is horizontal and parallel to the trend, or strike.

4. Fault Features Horst and graben are terms referring to regions that lie between normal faults and are either above or lower the area beyond the faults. A horst represents a block pushed upward by the faulting A graben is a block that has dropped due to faulting.

5. Folds During a mountain building, flat-lying sedimentary and volcanic rocks are often bent into a series of wavelike ripples called folds. Finds in sedimentary strata are much like those that would dorm if you were to hold the ends of a sheet of paper and then push them together. They come in a wide variety of shapes and sizes.

6. Types Of Fold The three main types of folds are anticlines, synclines, and monoclines. Anticlines are most commonly formed by the upfolding, or arching, of rock layers. Often found in association with anticlines are downfolds, or troughs, called synclines. Monoclines are large, step-like folds in otherwise horizontal sedimentary strata.

7. Resources Textbook http://en.wikipedia.org/wiki/Horst_and_graben http://www.britannica.com/EBchecked/topic/272443/horst-and-graben